


Would It Really Be A Sin?

by Sneakyfox55



Category: Undertale (Video Game)
Genre: Author Is Sleep Deprived, Because of Reasons, Blackmail, Books, Bookstores, Dark Comedy, Don't take it too seriously, Ever - Freeform, F/M, For a Friend, Jerks, Magic, Most of the time, ONE DIRTY JOKE, Reader just kind of rolls with everything, Reader still has morals, Sans is creepy, Still no smut, This will probably be pretty tame compared to other Yandere Sans fics, Weird Attempts at Comedy, Yandere Sans (Undertale), and a bit of a stalker, baby's first yandere fic, but he's also a sweetheart, do i have any idea what I'm doing?, high levels of sass, i mean why not, just a bit, mild violence, no but imma do it anyway, no smut but there's like, please go check out said friend, reader is female, thirsty bois, very weird standards, what can i say i like it spicyy, you're kinda evil
Language: English
Status: Completed
Published: 2020-03-25
Updated: 2020-03-25
Packaged: 2021-02-28 18:15:31
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 1,806
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23111563
Author URL: https://archiveofourown.org/users/Sneakyfox55/pseuds/Sneakyfox55
Summary: You're an average human, with an average life, and an average job working at the local bookstore.You also have a boyfriend, who just so happens to be a bit less average than you.And, well... A lot more overprotective.Like, a lot more.Speaking of which, should you go tell him to stop threatening those customers?
Relationships: Sans (Undertale)/Reader
Comments: 26
Kudos: 108
Collections: My stuff, Reader Insert, Undertale





	Would It Really Be A Sin?

**Author's Note:**

  * For [FullFandomFreak](https://archiveofourown.org/users/FullFandomFreak/gifts).



> i'm kind of nervous to post this??
> 
> like, i've never posted a yandere-character-based story before, and because of that im not entirely sure i did it right, but
> 
> anyway this is for FullFandomFreak, 
> 
> it's not much and probably kind of dumb but I hope you like it, I tried :') i probably don't even know how to write a yandere character, i dunno? and sorry it's kind of late, i had a hard time juggling the idea of it with school and all that's been going on atm. But honestly, it was fun to write! thank you so much for the support dude, it means a lot and i hope this kind of shows my gratitude at least a little haha

"That'll be thirty-ninety-nine, sir," you tell the old man at the counter; in response, he hands you a few bucks, totaling up to fifty dollars. You raise a brow only slightly before grabbing a handful of change from the cash register and going to hand it to him; only for him to gently push your hand away.

"Keep the change," he says with a kind smile, and you're about to question if it's a trick or not but he's already heading for the door with his massive bag of comic books slung over his arm.

"Uh--err--have a nice day!" you blurt after him quickly, frozen in your spot as you stare after him. Only after the door shuts behind him do you ease up, and jab the bills into the machine in front of you.

Not even a minute later, you hear the bells ring again, signaling the arrival of another person. You glance up, roll your eyes once goodnaturedly, then go back to counting up the amount of money you've received since working. 

"what, you're not even gonna give me a kiss?"

You snort. "I _guess_ I could," you drawl, putting a finger to your chin and pretending to think hard on the idea. "...As long as you didn't kill anyone."

"aw, c'mon babe. you know i wouldn't do that." He grins at you cheekily, but oh, you know better.

"Riiight. Come here."

As he comes over to you, you immediately hold out your palm face-up; he stares at it, then back at you, while you make a grabbing motion with your fingers.

"what?" he asks, innocently, purposely making it obvious he has one of his own hands behind his back.

"Give it here."

"give what?"

You deadpan in response, narrowing your eyes and his grin only broadens.

"Give me," you demand.

"you'll have to be more specific, sweetheart."

"I can tell you've been using your magic," you state.

"so?"

"Give me the bone!"

Almost instantly, you regret saying those words, as his eye-lights shrink into pinpricks. He practically doubles over in laughter, clutching his sides like it actually hurts him, and your own face heats up.

Despite your own smile twitching at your mouth, you snarl, " _Shuddup_ , you know what I mean!"

"do i?" he wheezes out, and you finally chuckle.

"Alright, I did walk into that one."

"yeah, ya did."

You roll your eyes, grabbing his arm and spinning him to face you directly.

"Seriously, though," you warn, "I know you like messing with me and all but get rid of it before another customer shows up."

He sighs out a prolonged, "fine," and shows his hand to you; you watch as the magic weapon dissolves in his palm like dust, leaving small, shiny particles to linger for a second or two.

"Well, assuming you've been good and didn't stab anyone with it... Yet," you add, after a pause. "I suppose I _should_ kiss you, hmm?"

Sans just blinks back, giving you the skeleton equivalent of puppy-dog eyes. You pretend to huff, then suddenly pull him forward by his shirt, pressing your lips against his teeth firmly. Just as quickly, you let him go, turning back to the cash register casually and pretending nothing ever happened as you count up the last of the money. Flippantly, you wave your hand at him, saying, "Now go read or something, I'm working."

He stares at the back of your head a moment, pupils having mutated to small hearts, before walking dazedly over to the science-fiction section.

* * *

The day goes on pretty smoothly, for the most part. You get the usual customers, monsters and humans alike.

It's not too crowded--it never really is, but there is a group of college kids that show up at one point. You've dealt with kids before, older and younger, so when one of them tries to hit on you you just laugh and shake it off.

(And wince inwardly because you know Sans is most definitely watching.)

Thankfully, they don't stay for too long and only buy a couple of books: one of them being a book about viruses, for whatever reason? But you're not here to question anybody, of course.

As they head for the door, you quickly shoot your boyfriend a pointed look, one that says, "Don't even think about it." He just snorts and continues flipping through the joke book he has in his hands, though you catch his gaze on the entrance of the shop more than once.

It's at five when things start to go downhill.

You simply hear the bell, at first, signaling the arrival of a new face as per usual. But then the guy shouts, "Hey, (Y/N)!" and you realize this is about to go up in flames; literally, depending on certain factors.

Still, you face him with a greeting smile, however strained it may be. "Hey, Chad."

Your smile falters as you feel the air shift around you, knowing Sans is no longer paying attention to his book.

Chad saunters up to your counter with confidence, slamming his hands down on the smooth wood and making you flinch slightly. "So how you been?" he says with a wide grin, and you have to force yourself to not grimace.

"Um, good. You?" you ask, politely, or, you try to be polite, anyhow.

"Good!" He goes to look at one of the shelves, and you have a brief moment of relief; very brief, as you look back at Sans, who's not looking at you.

"So, uh, what are you looking for today?" you go on with a watery smirk, pretending to seem friendly.

"Oh, nothing. Just browsing." Oh. "Kinda just wanted to see you," he adds. 

Crap.

_Crap._

"Chad," you begin, verging on the edge of warning; he doesn't pick it up and continues anyway, much to your annoyance:

"I mean, it's not every day a guy like me gets see a pretty face like you, right?" He turns to you, giving you a... Look you definitely do not like. "It's really a shame you're not single."

_...What._

Okay, this is new. He's never said something that weird.

He's said pretty weird stuff before, but... This probably takes the cake.

Is he high?

You straighten, peering at the man in front of you with narrowed eyes.

"Chad, I already told that I'm--"

"Not interested, yeah, I know," he waves his hand casually, and, _holy crap did he just interrupt you? AND disregard your words completely?!_

You can't help it. You're glaring now. You're peeved. No more Ms. Nice Cashier. "Don't take that tone with me," you say lowly.

"Oh please," he laughs, actually _laughs_. "I know you want me, babe. You don't say it but trust me, I know."

_What the heck?_

"How about we, y'know... Leave this place?" He raises a brow at you, suggestively, and you might just puke.

"No." You decide to turn around, hoping if he sees you're not paying any more attention to him, he'll give up.

"C'mon, (Y/N)--"

You hear three things in that moment:

One, is his voice being abruptly cut off.

Second, a loud _craaack!_

Third, a girl wailing--oh wait that's him.

You glance up to see said grown man lying on the floor in a fetal position, clutching his arm. He screeches out a couple of colorful words and you sigh.

"Sans, what did you do."

"shut him up," he says simply, pretending to look closely at a magazine you'd left on the counter.

"I was handling it," you argue.

"yeah but he was annoyin' me."

You sigh, again, and mutter, "Hand me my cell phone."

"why?"

"Just do it."

Sans huffs, but fishes your phone out of his hoodie; you're honestly not surprised. You snatch it from him with a slight glare before beginning to dial, then put it up to your ear.

A few seconds later, you hear a woman's voice on the other hand: "911, what's your emergency?"

"Hi, yes, so some guy broke his arm I think..."

* * *

Of course, when you call off work early, your boss has questions for you. You literally just tell her, "I'm going to the hospital" and leave it there for her to freak out over, because your sanity is running low by this point.

You also end up bring Sans with you--rather, he kind of just tags along without you telling him to. So now you're his babysitter, above all else.

When the doctor finally does let you two in to see him, he happens to be in the farthest room on the highest floor, and you're already crabby so when he happens to be awake and immediately starts _sneering at you,_ you can't help but ask bluntly, "How's the arm?"

On cue, Chad growls, "Freakin' broken thanks to your dumb boyfriend."

"Wow," you quip. "Lame. What happened to your colorful vocabulary?"

He sits up a little straighter, looking ready to fight you; honestly, you won't be surprised if he gets up out of bed and tries. "What, you _condone_ his behavior?"

"No," you say, rather calmly, given the situation. "But I'd be lying if I said you didn't deserve it."

"Why, you little--!"

"I'll pay for your bill."

As expected, his mouth falls open in a silent insult, and his eyes stretch wide. You just continue staring back at him with a level, serious gaze, trying to prove your integrity.

"Is this some sort of trick?" he demands, after a moment. You shake your head.

"My boyfriend beats you up, I deal with the injury cost. It's a win-win, right?" you reply with a slight smile.

"...You've gotta be kidding."

"Nope. I'm serious. I've dealt with this before, I know what I'm doing." You hear Sans scoff behind you, but ignore him. "So, do we have a deal or not?"

Chad narrows his eyes at you, chewing his lip, the gears obviously turning in his head.

"Yeah," he grumbles, reluctantly.

"Great!" You beam at him, then quickly turn to your boyfriend. "Come on, let's get out of here."

You usher him out, almost forcefully as he sends Chad a creepy grin before letting you redirect him into the hallway. Before following suit, you pause in the doorway, glancing back.

"Oh, by the way... I'd really appreciate it if we kept this between the three of us, okay?" You click your tongue, "I've seen your bank account, so... Yeah. Say anything, consider our deal broken too." 

Before he can do much more than blink at you, you spin on your heel and catch up to Sans. He quirks a bone-brow at you, but you just chuckle and entwine your fingers with his, beginning to pull him along once more.

Honestly, you're not too worried about this.

I mean, who's going to believe a guy named _Chad_ anyway?

**Author's Note:**

> hahaha did ya see the corona reference
> 
> hahahaha _~~infect me now, Lord~~_
> 
> oh and, COMPLETELY unrelated but I found my new favorite song you can listen to it here: https://www.youtube.com/watch?v=7qMXBUjm8tM


End file.
